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"How Finalization Affects Collection
When the garbage collector first encounters an object that is otherwise dead but still needs to be finalized it must abandon its attempt to reclaim the space for that object at that time. The object is instead added to a list of objects needing finalization and, furthermore, the collector must then ensure that all of the pointers within the object remain valid until finalization is complete.
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Since the internal object pointers must remain valid, not only will the objects directly needing finalization linger in memory but everything the object refers to, directly and indirectly, will also remain in memory. If a huge tree of objects was anchored by a single object that required finalization, then the entire tree would linger, potentially for a long time as we just discussed."
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